“MessageGroupStore”中只能注册一个“UniqueExpiryCallback”实例

在里面

    org.springframework.integration.store.AbstractMessageGroupStore {
    ...
    @Override
    public void registerMessageGroupExpiryCallback(MessageGroupCallback callback) {
        if (callback instanceof UniqueExpiryCallback) {
            boolean uniqueExpiryCallbackPresent =
                    this.expiryCallbacks.stream()
                            .anyMatch(UniqueExpiryCallback.class::isInstance);

            if (!uniqueExpiryCallbackPresent && this.logger.isErrorEnabled()) {
                this.logger.error("Only one instance of 'UniqueExpiryCallback' can be registered in the " +
                        "'MessageGroupStore'. Use a separate 'MessageGroupStore' for each aggregator/resequencer.");
            }
        }

        this.expiryCallbacks.add(callback);
    }
   ...
}

它是spring集成的5.1.1版本。